This invention relates to the generation of a video signal from play of a software (e.g., motion picture) carrier, and more particularly to a technique by which a video signal can be generated in a selected one of multiple aspect ratios upon play of a disk recorded in only a single aspect ratio.
In accordance with the principles of the invention, a software publisher provides a software carrier which contains digital data representative of a motion picture having a base aspect ratio. Preferably, the base aspect ratio is a 16:9 xe2x80x9cwide screenxe2x80x9d image. (It is to be understood that the invention is not limited to a particular medium, and it is applicable to tape carriers and all digital storage media, not just the optical disks of the illustrative embodiment of the invention. Nor is the invention limited only to the distribution of motion pictures. For example, in an extreme case, the invention is applicable to the distribution of a library of still pictures, in which case there is no xe2x80x9cmotionxe2x80x9d at all. The term xe2x80x9csoftware publisherxe2x80x9d thus embraces much more than a motion picture company, and the term xe2x80x9ccarrierxe2x80x9d embraces much more than a digitally encoded optical disk.)
The player is designed to process the digital data read from the carrier and to generate a corresponding analog video signal. The carrier contains a code indicative of the recorded aspect ratio. (There is no invention per se in having the carrier include data which is indicative of the recorded aspect ratio. The issue is what the player does with the invention.) The player can generate the video signal in the same wide screen aspect ratio represented on the carrier. However, the user of the player can select a different aspect ratio. One such aspect ratio is 4:3 letter box. The conversion can be best understood by considering two rectangles having the same height but respective width: height ratios of 16:9 and 4:3. If the former is reduced in size so that it can be wholly contained with the latter, it is apparent that the vertical sides of the 16:9 image must be brought closer together. This, in turn, results in the top and bottom sides also being brought closer together. When the reduced-sized 16:9 image is centered in the 4:3 rectangle, there are left-over bands at the top and at the bottom. Similarly, when a wide screen motion picture is displayed on a conventional 4:3 aspect ratio television receiver, the top and bottom of the screen are usually blanked (dark).
But an alternative to reducing a 16:9 image so that it fits on a 4:3 screen is to display just a 4:3 cut from the wide screen image. Given 16:9 image and 4:3 screen rectangles of the same height, it is apparent that when the smaller screen rectangle is placed on the larger image rectangle, the only picture information which is displayed is that within the 4:3 rectangle. What is lost in such a case is picture information on the left side or the right side, or both sides, of the wide screen image. One way in which to convert from a 16:9 to a 4:3 aspect ratio (and to fill up the 4:3 screen rather than to blank out the top and bottom of the screen as in a letter box presentation) is to select the middle part (a xe2x80x9ccenter cutxe2x80x9d) of each wide screen image for display, in effect deleting equal sections from the left and right sides of the original image.
The invention, however, provides for a more sophisticated control over which part of the wide screen image is selected for viewing. The software carrier itself contains pan scan information which can change from one part of a motion picture to another. Referring to the discussion above about fitting a 4:3 screen rectangle on a larger 16:9 image rectangle to determine how much of the wide screen image is actually selected for viewing, a pan scan of the wide screen image involves moving the 4:3 rectangle in the horizontal direction. If the rectangle is all the way to the left, then what is deleted is the right side of the wide screen image. Alternatively, moving the 4:3 rectangle all the way to the right cuts out the left part of the wide screen image. But the 4:3 rectangle can be moved anywhere between the two extremes. This allows the software publisher to choose which part of the wide screen image is displayed at any given time. The disk of the invention can be provided with continuously changing pan scan information representative of what vertical line through the wide screen image corresponds to the left edge of the 4:3 rectangle selected for viewing. The player of the invention automatically generates a video signal which represents the selected part of the wide screen image. (From an engineering point of view, it is well known in the art how to accomplish a pan scan. For example, this is the way software publishers today sometimes reduce a wide screen motion picture to a 4:3 aspect ratio for recording on a software carrier. It is because conventional players cannot convert a wide screen aspect ratio on a carrier to multiple aspect ratios required for display on different television receivers, thus making it necessary to produce a unique carrier for each aspect ratio, preferably with a pan scan of the wide screen original, that there is a need for the present invention.)
The player of the illustrative embodiment of the invention plays disks recorded in one of only two aspect ratios, 16:9 or 4:3. (These are today""s xe2x80x9cstandardxe2x80x9d electronic display formats, but it should be understood that the principles of the invention are equally applicable to other aspect ratios.) These two aspect ratios, however, give rise to more than just two possibilities. As described above, the output aspect ratio can be the original 16:9 in letter box form, the output can be a 4:3 center cut from a 16:9 wide screen image, or the output can be a pan scan cut from the original. (Of course, the output can also be in the original 16:9 format.) The player has a default aspect ratio, by which is meant that the player automatically generates a video signal having the default aspect ratio. The user can change the default setting. The advantage of providing a default setting is that play is automatic and the user has one less control to worry about. Only in the case of an ambiguity is the user asked for his preference. For example, if the player default is pan scan 4:3 and the disk is recorded in a 16:9 aspect ratio but does not contain pan scan update information, then the player has no way of knowing which part of the wide screen image should be played. In such a case, the user is given a choice between a center cut and a letter box form of display.
The invention offers an additional benefit to motion picture companies. It might be thought that with xe2x80x9cuniversalxe2x80x9d players in the hands of consumers, players which can generate video signals not only in multiple standards (as will be described below) but also with different aspect ratios, a motion picture company would distribute disks recorded only in a wide screen formatxe2x80x94this base aspect ratio allows for the generation of the best possible picture for all TV receivers (e.g., wide screen for wide screen receivers, reduced aspect ratios for older type receivers, etc.). However, a motion picture company may deliberately release a xe2x80x9cfilmxe2x80x9d having a 4:3 aspect ratio. This allows for the release at a later data of an xe2x80x9cimprovedxe2x80x9d version with a wide screen aspect ratio, and perhaps other enhancements as well. The point is that if consumers have players that can generate video signals in a selected one of many different aspect ratios, then the software publishers can re-release programs in improved formats and thus make additional sales.
Nevertheless, the main advantage of the invention is that a software publisher no longer will have to release dedicated aspect ratio versions of the same motion picture. Because of inventory, cost, promotion, contractual or financial considerations in releasing multiple versions of the same program, some publishers today do not or cannot release dedicated aspect ratio versions of all titles, and some distributors and retailers do not or cannot stock them. The present invention overcomes these problems because a single recording will allow video signals to be generated in multiple aspect ratios.
It should also be appreciated that the invention is almost the converse of that taken in the design of certain wide screen television receivers now being marketed in the United States and Japan under the trademarks Thomson, Toshiba, JVC and others. These television receivers take a 4:3 image, the most prevalent standard today, and blow it up to fill the 16:9 screen. Separate and apart from image degradation which can be seen on the screen, such an approach involves a conversion from 4:3 to 16:9, rather than the reverse. One of the goals of the invention is to provide on the carrier an aspect ratio from which many others may be derived with minimum degradation of the image. It is therefore better to start with xe2x80x9cmorexe2x80x9d on the disk than xe2x80x9cless,xe2x80x9d i.e., to go from 16:9 to 4:3.
The invention is disclosed in the context of an overall system which offers numerous advantageous features. The entire system is described although the appended claims are directed to specific features. The overall list of features which are of particular interest in the description below include:
Video standard and territorial lock out.
Play in multiple aspect ratios.
Play of multiple versions, e.g., PG-rated and R-rated, of the same motion picture from the same disk, with selective automatic parental disablement of R-rated play.
Encrypted authorization codes that prevent unauthorized publishers from producing playable disks.
Provision of multiple-language audio tracks and multiple-language subtitle tracks on a single disk, with the user specifying the language of choice.
Provision of multiple xe2x80x9cotherxe2x80x9d audio tracks, e.g., each containing some component of orchestral music, with the user choosing the desired mix.
Variable rate encoding of data blocks, and efficient use of bit capacity with track switching and/or mixing, to allow all of the above capabilities on a single carrier.